The present invention relates to fluorinated phenylethynylaniline (PEA) compounds. In a further aspect, this invention describes the preparation of fluorinated phenylethynylaniline compounds. Although these compounds are directed toward use as capping reagents in high temperature stable polyimides, they can be used for any polymer having suitable reactive functionality. Tis invention also relates to the preparation of fluorinated acetylene containing aromatic-diamines useful as monomers in step-growth polymerizations.
U.S. Pat. No. 4,594,352, issued June 10, 1986, discloses benzoyl-urea derivatives (derivatives of 1-benzoyl-3-aryl-urea) having high insecticidal activity. Two of the monoamine compounds of the cited patent are structural isomers of the compounds disclosed and claimed in the present invention. The key difference is that the compounds described in the present invention which are isomeric with those disclosed in U.S. Pat. No. 4,594,352 contain the amine nitrogen atom in a position which is meta to the acetylenic carbon, whereas the related prior art compounds contain the amine nitrogen in the para position. It is generally recognized by organic chemists that aryl acetylene compounds containing an electron donating group in the para position increases the rate of hydration of the acetylene to the corresponding ketone. Although hydration is normally carried out under acidic conditions in the presence of a mercuric salt, it has been shown to occur with p-aminophenylacetylenes (p-ethynylanilines) under the conditions of thermal imidization used to prepare certain polyimides. See Polymer Preprints, 21 (1), 81 (1980). Consistent with the intended use of these compounds (see formula I) as reactive capping reagents in which crosslinking occurs through the acetylene group, it is imperative that the acetylene moiety be resistant to hydration. Thus, it is a feature of the present invention that the m-substituted phenyl acetylene compounds herein are less subject to undesired hydration.
As stated above, the fluorinated acetylene containing amines of the invention are useful as capping reagents in any oligomer or polymer having functionality which can undergo reaction with the amine to form a stable adduct. The resulting aryl acetylene capped oligomer can be utilized, for example, as matrices in fiber reinforced composites or as the neat resin itself in the preparation of molded parts. Other uses include application in the microelectronics industry as an adhesive or coating. On further heating, the aryl acetylene undergoes a crosslinking reaction to give the final thermoset resin. The high temperature at which this reaction occurs provides a large window during which the oligomer or polymer can be processed in bulk. A detailed description of the use of these compounds as capping reagents is given in co-pending patent application (Ser. No. 07/482,362 filed Feb. 20, 1990) to C. Paul, et al.
The diamine compounds of the invention are useful as step-growth monomers in the preparation of polymers containing reactive acetylene groups in the polymer backbone which are capable of undergoing a further crosslinking reaction to give thermoset resins of high mechanical integrity. These monomers are particularly suitable in the preparation of thermally stable polyimides.